Mutated or overexpressed proteins are associated with several types of malignancies of the lung, breast, stomach, head, neck, colorectal cancer, pancreatic carcinomas, glioblastoma, and some appendiceal cancers, with the latter being associated with mutations in EGFR/ERBB1 (7p11.2), HER2/ERBB2 (17q12), and HER4/ERBB4 (2q34) genes, unlike other family members. The gene discussed is ERBB4; the disease is exocrine pancreatic carcinoma.